1. Field of the Invention
The present invention relates to a mobile terminal device and a method of updating a program stored therein.
2. Description of the Related Art
Update data are transmitted from a base station through a radio section to a mobile terminal for updating a program stored in the mobile terminal to obtain the new version of the program, wherein the program may, for example, be a system software for transmitting and receiving radio signals. Japanese lid-open patent publications Nos. 11-239094 and 11-298959 disclose the conventional methods of updating the program stored in the mobile terminal to obtain the new version of the program.
First one of the updating methods is that the entirety of the program is updated. Second one of the updating methods is that only a difference between the old version of the program stored in the mobile terminal and the new version of the program is selectively updated. In either of the methods, the updated data transmitted from the base station through the radio section are down-loaded into the mobile terminal for updating the program stored in the mobile terminal.
The conventional methods of updating the programs stored in the mobile terminal have the following disadvantages. A communication between the base station and the mobile terminal may be interrupted due to any defect of the electric field an the radio section or a voltage drop of a battery power of the mobile terminal. If a disconnection between the base station and the mobile terminal appears in the radio section during the transmission of the update data from the base station to the mobile terminal, then the transmission of the update data of the program stored in the mobile terminal is incomplete.
In accordance with the conventional updating methods, if the download of the update data into the mobile terminal is incomplete due to any interruption of the transmission, then the communication system do over the transmission of the update data again. This conventional method is the time-consuming method if the interruption of the transmission appears.
Even if the download of the update data into the mobile terminal is complete, and if the downloaded data include any defective data, then the updated program performs an abnormal function. The actual execution of the updated program makes it possible to verify whether the updated program is defective or non-defective. The conventional methods are enable to verify whether the updated program is defective or non-defective without actual execution of the updated program. If the defectiveness of the updated program could be verified after the actual execution of the updated program, then it is necessary to again download the updated program into the mobile terminal. This procedure is inconvenient for the user of the mobile terminal.
In the above circumstances, the development of a novel method of updating the program stored in the mobile terminal free from the above problems is desirable.